The present invention relates radio communications systems, and more particularly to digital radio communications systems. Even more particularly, the present invention relates to transport modes in a radio communications system.
Radio communications devices are commonly known in the art of communications. A radio is a device that transmits and receives electromagnetic energy being within the range of frequencies known as radio frequency. Radios are commonly used in communications systems as a means to transmit and receive communications over a wireless communications link. Prior art radios have many applications, such as in FM broadcast radio, mobile cellular communications, point to point communications systems, and point to multipoint communications systems.
Radios carry many types of information in the form of signals and are often used in radio communications systems, such as a point to point communications system or a point to multipoint communications system. These signals may be transported over the radio interface using transport modes that are known in the art. One such transport mode or transmission mode used is xe2x80x9csynchronousxe2x80x9d transport mode. Synchronous translates from its roots to mean xe2x80x9ctogether with timexe2x80x9d. Thus, synchronous transport mode signals are sent according the time that the signals are configured to be sent. As an example, in time division multiplexed (also referred to as TDM) signals are sent as packets (of data) within a particular timeslot. At the receiving end, the packets are sorted according to which timeslot that they were located in. Thus, in a TDM radio, overhead messaging is not needed within the packet for routing. Most common radio communications systems use TDM.
Another form of transport is xe2x80x9casynchronousxe2x80x9d transport mode which translates from its roots to mean xe2x80x9cnot together with timexe2x80x9d. In an asynchronous radio system, asynchronous signals are sent as packets (of data) without regard for which time they are being sent. The asynchronous packets require overhead messaging within the packet for routing at the receiving end. One example of asynchronous transport that is gaining popularity as a high speed data carrier is called asynchronous transfer mode (also referred to as ATM). ATM is a high speed, packet switched architecture that integrates voice, data, video, and multimedia images. ATM outperforms TDM as a high speed data carrier, but the quality of service for voice is less known than TDM. ATM is desirable for large companies, universities, and financial institutions that have a wide variety of telecommunications needs.
Prior art radios only carry one type of traffic or the other, depending on the configuration. Thus, a first radio could be configured to carry synchronous traffic (signals), but the first radio would be unable to carry asynchronous traffic (signals). Furthermore, it is desirable for subscribers of commercial radio communications systems to use a TDM-based radio communications system to obtain voice services and to use an ATM-based radio communications systems to obtain data services. However, a subscriber must subscribe to separate radio communications systems to get the benefits of both TDM and ATM services. Disadvantageously, if a single service provider could provide both TDM and ATM services, the service provider would need to create two separate radio communications systems, each having separate infrastructure, including radios, compatible with both synchronous traffic (e.g. TDM) and asynchronous traffic (e.g. ATM).
The present invention advantageously addresses the needs above as well as other needs by providing a radio and related methods of radio communication, that supports multiple transport mode. Advantageously, the radio supports both synchronous transport mode signals, such as TDM traffic, and asynchronous transport mode signals, such as ATM traffic.
In one embodiment, the present invention can be characterized as a radio including one or more signal formatters, wherein the one or more signal formatters format signals for transmission through the radio and wherein the signals comprise a plurality of transport mode signals. The radio also includes a modem coupled to the one or more signal formatters for modulating the signals, a frequency converter coupled to the modem for upconverting the signals having been modulated to a radio frequency, and a transceiver unit coupled to the frequency converter for transmitting the signals having been upconverted over a radio communications link.
In a further embodiment, the present invention can be characterized as a method, and means for accomplishing the method, of radio transmission over a radio communications link comprising the steps of: formatting signals for transmission through the radio, wherein the signals comprise a plurality of transport mode signals; relaying the signals to a modem; formatting the signals for transmission over the radio communications link; modulating the signals for transmission over the radio communications link; converting the signals to a radio frequency of the radio communications link; and transmitting the signals over the radio communications link.
In an additional embodiment, the present invention can be characterized as a method, and means for accomplishing the method, of radio reception from a radio communications link comprising the steps of: receiving signals from the radio communications link, wherein the signals comprise a plurality of transport mode signals; converting the signals to a digital baseband; demodulating the signals; mapping the signals to a multi-transport mode bus frame format; transporting the signals via the multi-transport mode bus to an interface module; and routing respective ones of the signals to respective communications lines.
In yet another embodiment, the present invention can be characterized as a method of radio transmission in a single radio comprising the steps of: converting modulated signals to a radio frequency, wherein the modulated signals comprise a plurality of transport mode signals; and transmitting the modulated signals over a radio communications link.
In a further embodiment, the present invention can be characterized as a method of radio transmission over a radio communications link comprising the steps of: providing a multi-transport mode radio adapted to transmit signals over a radio communications link, wherein the signals comprise a plurality of transport mode signals; establishing the radio communications link coupled to the radio.